Air intake governor for heating devices



Search Room May 30, 1944. R. MARTIN 2,349,876

AIR INTAKE GOVERNOR FOR HEATING DEVICES Filed Aug. 16, 1941 sSheets-Sheet 1 INVENTO ATTbRNEY May 30, 1944.

R. MARTIN AIR INTAKE GOVERNOR FOR HEATING DEVICES Filed Aug. 16, 1941 3Sheets-Sheet 2 INVENTOR fiusse/l Mar/in.

ATTONEY I Search Roo y 1944- R. MARTIN 2,349,876

AIR INTAKE GOVERNOR FOR HEATING DEVICES Filed Aug. 16, 1941 3Sheets-Sheet 3 IENTOR Fusswel/ Nerf/h A! ZRNEY [I stttstous Built-5.;

7 Patentetl May 30, 1944 Search Room AIR INTAKE GOVERNOR FOR HEATINGDEVICES Russell Martin, Wichita, Kans., assignor to The Coleman Lamp andStove Company, Wichita, Kana, a corporation of Kansas Application August16, 1941, Serial No. 407,156

15 Claims.

This invention relates to fuel burning appliances and particularly to anair intake governor therefor.

In the use of appliances having fuel combusting burners many attemptshave been made to control the draft, supplying combustion supporting airto the burner. The usual practice has been to employ the pressuredifferential be tween the interior of the device and exterioratmospheric air to actuate some sort of damper attempting to reduce avariable excess draft to an operating draft which will ratio interiorpressure to atmospheric pressure so that substantially the amount of airneeded for efficient combustion will be supplied.

Frequently a damper is introduced within the hot and sooty vents needfulfor exhausting the products of combustion. Movable parts of this damperdevice often become fouled with carbon deposit and corrosion so that itfails to respond quickly, and at times may completely fail causingdangerous living conditions within the house where the appliance isused. As a matter of practice for safety purposes such dampers areusually limited to eighty per cent closure and are, therefore, limitedin range of control and inaccurate under some conditions.

It is also common practice to use a damper device to admit atmosphericair directly into the flue vent thus reducing the flow of air throughthe burner. This has in a measure compensated for the wide variation inchimney drafts, but due to gusty winds and variable weather conditionsthese "air regulators which operate through a very limited range, areoften not sufficiently accurate to effect high efficiency in the burneroperation. In certain types of heating equipment they also exhaust fromthe space being heated a portion of the warmed air which must bereplaced by cold air infiltrated from the outside thus further reducingeffective efficiency.

Air intake controls have also been used, but these have not beenautomatically coordinated with the variations of natural chimney draft,so that a substantially constant and uniform supply of combustionsupporting air for the burner has not been obtained.

Mechanical devices, such as electrically operated blowers, have alsobeen employed in an attempt to secure uniform flow of air to the burner.Since these of necessity must be operated in connection with thevariable natural draft produced by the chimney vents the combined resulthas been a variable air supply for the burner.

It is my belief that my invention is a very obvious improvement upon alldevices hitherto used for this purpose because it does not attempt tocontrol an interior pressure (as others have done) to effect the desiredpressure ratio with exterior atmospheric air to create a uniform draft,but it does maintain a substantially uniform pressure differentialbetween two chambers having restricted passage between them throughwhich combustion supporting air flows.

Thus it effects a substantially constant differential of pressurebetween certain areas within the appliance which pressure differentialdetermines the amount of combustion supporting air passing through theappliance.

The principal object of this invention, therefore, is to provide adevice which will deliver to the burner of a fuel burning appliance asubstantially constant and uniform supply of combustion supporting airregardless of chimney draft variables and also regardless of anyvariable affecting the flow of atmospheric air to the appliance.

Other objects of the invention are to provide an air intake governorwhich can be readily built into small household appliance thus producinga desirable unitary structure; to provide an air intake governor whichis adapted to factory adjustment for the burner employed, whichadjustment is not affected by the variable excess chimney draftsencountered when the appliance is installed for use; to provide an airintake governor which does not have to be readjusted when a mechanicalforced draft device is used in combination with natural chimney draft;to provide an air intake governor adapted to coordinated control withthe fuel feeding device of the appliance to secure maximum efficiency atall burning rates; and to provide an air intake governor that is simpleand inexpensive to manufacture.

It is also an object of the invention to provide an air intake governoradapted to coordinated control with the fuel feeding device of theheating appliance.

In accomplishing these and other objects of the invention, ashereinafter described, I have provided improved structure, the preferredform of which is illustrated in the accompanying drawings, wherein:

Fig. 1 is a plan view of a floor furnace embodying the features of thepresent invention, a

part of the combustion chamber being broken away to better illustratethe construction.

Fig. 2 is a vertical section through the lower gortilon of the floorfurnace on the line 2-2 of Fig. 3 is a vertical cross-section throughthe furnace on the line 33 of Fig. 1, the air intake governor beingshown in elevation.

Fig. 4 is a fragmentary cross-section through the furnace on the line4-4 of Fig. 1.

Fig. 5 is a cross-section through the air intake governor on the line5--5 of Fig. 6.

Fig. 6 is a central longitudinal section through the air intakegovernor.

Fig. '7 is a cross-section on the line 1-4 of Fi 6.

Fig. 8 is a perspective view of the parts of the air intake governorshown in disassembled spaced relation.

Referring more in detail to the drawings:

I designates a heating appliance embodying the present invention andwhich may be an oil burning floor furnace, however, it is to beunderstood that the invention is applicable to any type of heatingappliance employing a combustion or burner chamber requiring acontrolled supply of combustion supporting air for maintaining maximumefficiency.

The floor furnace illustrated includes an outer casing 2, adapted to besuspended in a floor opening 3 and which has opposite side walls 45 and6--'| and a bottom 8, the top being covered by a floor grill 9.Supported within the outer casing 2 is an inner casing l0, havingvertical walls spaced from corresponding walls of the outer casing toprovide downdraft air passages ll' wherethrough air to be heated iscirculated from the room and moved upwardly through the inner casing inheating contact with a heater unit l2 and returned to the room throughthe grill 9.

The heater unit l2 includes a combustion chamber l3 separate from aburner or air supply chamber l4 by a transverse partition I5. Thepartition i5 has a depressed bottom portion 16 at a side thereof whichregisters with the lower portion of a flue outlet ll extending throughthe inner and outer casings and adapted to be connected with a vent orchimney by means of a smoke pipe (not shown). Supported in an opening atsubstantially the center of the partition is a chamber or burner pot l8which, in the illustrated instance, has a cylindrical wall IS, a closedbottom 20, a low fire ring 2| spaced from the bottom, and a high flrering 22 seated on a peripheral flange 23 secured to the partition l5.Fuel is supplied to the burner pot by way of a pipe 24 having connectionwith a constant level and fuel control valve 25 which in turn isconnected by a pipe 26 with the burner pot. The fuel control valve 25 isregulated by a rod 21 which extends upwardly within one of the downdraftpassages II and terminates in a handle 28 adjacent the grill so thatwhen the grill is removed the rod may be rotated thereby to adjust theamount of fuel admitted to the burner pot.

Combustion supporting air is admitted under restriction to the chamberor burner pot l8 from the air supply chamber l4 through restrictingopenings 29 which are provided in the cylindrical wall l9, as best shownin Fig. 4, the supply chamber being provided with an air inlet opening30 in the wall thereof so that a portion of the air circulated throughthe downdraft passages is admitted to the supply chamber responsive todraft.

Heating appliances of the character described operate most efficientlyat a predetermined draft or pressure differential but when installedthere is no assurance that the device will be operated at the desireddraft for the reason that it may be connected with a chimney having adraft greatly in excess of that required, or the chimney may have barelysufficient draft to support combustion. It is true that a draft controlis usually connected in the smoke pipe so as to admit a sufficientamount of exterior air to the chimney in such a manner that theeffective draft approximates the predetermined draft but, as abovepointed out, such regulators do not operate satisfactorily and are notsufiiciently sensitive to maintain the predetermined draft for which theappliance is designed.

While the present invention may contemplate use of a draft regulator inthe smoke pipe in order to maintain roughly an approximate draft in theheating appliance, I provide the heating appliance with an air intakegovernor which is designed to operate automatically responsive topressure differential between the combustion chamber and the air supplychamber and which is adapted to control automatically the inlet of airnecessary to maintain efflcient combustion at the pressure differentialor draft for which the heater was designed and to maintain thispredetermined draft, regardless of varying chimney draft.

In carrying out the invention, the opening 30 is located opposite to theflue connection H, as shown in Figs. 1 and 3, and inserted therein is anair intake governor 3| which forms a unitary part of the heatingappliance.

The air intake governor is best illustrated in Figs. 5 to 8 inclusive,and includes a shell 32 having a cylindrical wall 33 of suitablediameter to be received snugly within the opening 30. The inner end ofthe cylindrical wall is closed by a head 34 having an opening 35 thereinregistering with the depressed bottom portion l5 of the partition IS.The opening 35 is encircled by a flange 36 which extends into an opening31 formed in the offset portion 38 of the partition as shown in Fig. 3.The op osite end of the shell is closed by an inset head 9 having aflange portion 40 engaging the inner face of the annular wall 33 andwhich is provided with a laterally extending rim 4i abutting against acorresponding rim 42 on the shell, as shown in Fig. 6. Air is admittedto the interior of the shell through a substantially sector-shapedopening 43 that is formed in the head 39 and which is of sufficientcapacity to pass adequate combustion supporting air to the air supplychamber by way of openings 44 formed in the cylindrical wall 33. Fixedto the inner face of the cylindrical wall 33 and extending inwardlytoward the axis of the shell is a partition 45. The partition 45 islocated so that it extends from one radial edge of the air inlet openingto the head 34 and cooperates with a vane 43 in dividing the shell intolow and high pressure chambers 41 and 48, the low pressure chamber 41being connected with the combustion chamber through the opening 35 andthe high pressure chamber being connected with the air inlet opening 43and outlet openings 44.

The vane 46 closely conforms to the walls of the shell and is mounted ona shaft 49 located in the axis of the shell and journalled in suitablebearing openings 50 and 5| formed in the heads 34 and 39. The vane 46is, therefore, adapted to swing within the shell responsive to pressuredifferential in the respective chambers. For example, should thepressure in the combustion chamber become less, the vane will swing inthe direction of the opening 35 and should the pressure increase in thecombustion chamber the vane will swing in the opposite directionresponsive to a weight 52 attached to an endless chain 53 operatingwithin the groove 54 of a pulley 55 attached to the outer end of theshaft 49.

In order to control the air intake responsive to a predeterminedpressure differential in the supply and combustion chambers, the shaft49 carries a shutter 56 comprising a substantially semicircular diskhaving a radial edge 51 thereof connected with the adjacent edge of thevane 46. The shutter 56 moves in close relation with the inner surfaceof the head 39 and in valving relation with the air inlet opening 43.Thus the effective area of the inlet opening is dependent upon apredetermined pressure differential between the high and low pressuresides of the vane as set by the weight 52. In order to limit maximummovement of the vane the shell is provided with stops 58 and 59respectively engaged by the vane and the shutter.

It is essential that the vane and shutter be initially counterbalancedprior to application of the weight 52 so that positioning of the shutteris the result of balancing the differential forces acting on the vanewith the weight 52. Therefore, I provide the shaft with an arm 60 havinga weight 6|. The weight has a relatively large axial opening 62 foradjustable mounting thereof on a stud 63 projecting from the arm 60, theweight being retained in adjusted position by a nut 64 threaded on thestud and arranged to draw a washer 65 into clamping engagement with theweight and the weight into clamping contact with the arm 60, therelative diameters of the opening in the weight and stud being such asto provide adjustment necessary in effecting the proper counterbalance.It is obvious that by providing a weight 52 of proper size, the vane maybe maintained in such a position that the desired amount of air isadmitted to the inlet opening of the supply chamber for maintaining apredetermined draft or pressure differential.

Owing to the fact that the air intake governor is located in the path ofthe combustion supporting air supply, it is maintained in relativelycool condition so that close tolerances may be effected between theshell and the moving parts of the governor. Also there will be noaccumulations of soot or the like to clog the operation thereof. Furtherthe parts may be of small size and capacity because the air isrelatively cool and of small volume.

The heater will operate at maximum efficiency at a given burning rate,but if the burning rate is changed it is desirable to change thedifferential pressure. This is accomplished by varyin the effectiveforce or leverage of the weight 52 on the pulley 54 responsive to changeof the fuel valve setting.

The head 39 carries a collar 66 in encircling relation with the shaft toform a pivotal support for an arm 61 whereby the arm is free to pivotabout the axis of the shaft without interfering with freedom of thegovernor vane. Carried by the free end of the arm 61 is a stud 68journalling an idler pulley 59 and having a peripheral groove therein toaccommodate the chain 53. Fixed to the stud 68 is a yoke H havingconnection with a cam 12 on the valve rod 21 through a flexibleconnection 13. The flexible connection 13 operates over a guide pulley14 fixed to a bracket 15 whereby the end of the flexible connection,which is attached to the cam, is supported in a horizontal plane and theother end is supported on a plane extending through the axis of theidler pulley 59. With this arrangement, manipulation of the valve rodcauses movement of the idle pulley in an are about the axis of thegovernor shaft so as to vary the leverage of the weight 52. For example,when the weight 52 is depending tangentially of the pulley 54, theweight 52 exerts maximum leverage on the pulley so that a greaterdifferential force is required to move the shutter toward closedposition and a greater differential effects increased flow of air intothe supply chamber to maintain the proper air and fuel ratio for maximumefficiency. When the valve rod is rotated in a counter-clockwisedirection to throttle the feed of fuel to the burner pot, the idlerpulley is moved to the right, Fig. 1, so that the effective leverage forthe weight 52 on the pulley is lengthened with the result that thegovernor will be actuated by a higher pressure differential and more airwill be admitted to the burner pot to maintain the proper ratio with theincrease of the fuel feed.

From the foregoing it is obvious that I have provided a heatingappliance such as a floor furnace with an air intake governor forming aunitary part thereof and which is capable of maintaining a constantlyuniform draft or pressure differential regardless of excess variation inthe chimney draft. It is also obvious that the pressure differentialmaintained by the air intake governor is readily coordinated with thefuel adjustment so that the draft or differential is regulated inconformity with the burning rate of the fuel to maintain maximumefllciency under all operating conditions.

What I claim and desire to secure by Letters Patent is:

1. In a fuel burning appliance, the combination of a combustion chamberhaving a variable internal pressure, an air supply chamber having aninlet for exterior air, means for supplying fuel to the appliance, meansresponsive to pressure differential between said chambers for governingadmission of air through said inlet for maintaining a predetermined rateof air flow through said appliance, and means for changing the rate ofair flow responsive to change in rate of fuel supply.

2. In a fuel burning appliance, the combination of a combustion chamberhaving a connection adapted to be connected with a flue for effectingvariable pressure in the combustion chamber, an air supply chamberhaving an inlet for exterior air, means for supplying fuel to theheating appliance, means responsive to pressure differential betweensaid chambers for governing admission of air through said inlet forsupporting combustion of the fuel, means for controlling the fuelsupply, and means connected with the fuel control means for changing thepressure differential.

3. In a fuel burning appliance, the combination of a combustion chamberhaving a connection adapted to be connected with a flue for effectingvariable pressures in said chamber, a

burner having connection with said chamber, a

supply chamber for admitting combustion sup porting air to the burnerand having an air inlet, a movable vane responsive to pressuredifferential in the respective chambers, a throttle for the air inletactuated by the vane, means for applying a force to the vane to balancethe force of the required differential, means for supplying fuel to theburner, means for controllin the fuel supply, and means responsive tomovement of the fuel control means for varying the effect of the forceapplying means.

4. In a fuel burning appliance, a combustion chamber having a flueconnection through which variable pressures are effected in saidchamber, a burner associated with the chamber, a supply chambersurrounding the burner for admitting combustion supporting air andhaving an air inlet, a movable vane responsive to the variation of thedifferential pressure in th respective chambers, and means connectedwith the vane for valving the air inlet to said air supply chamberresponsive to movement of the vane.

5. In a fuel burning appliance, a combustion chamber having a flueconnection adapted to be connected with a flue for effecting variablepressures in said chamber, a burner having connection with said chamber,a supply chamber surrounding the burner for admitting combustionsupporting air and having an air inlet, a vane responsive to variationof the differential pressure in the respective chambers, a throttle forthe air inlet actuated by the vane, means for applying a predeterminedcounteracting force to oppose the higher of said pressures to effect thedesired pressure differential, and means for varying the counteractingforce to vary th pressure differential.

6. In a fuel burning appliance, a combustion chamber containing variablepressures when appliance is in operation, a burner having connectionwith said chamber, a variable supply chamber for admitting combustionsupporting air to the burner and having an air inlet, said burnerforming a restricted air flow connection between said chambers, a vaneresponsive to differential of pressures in the respective chambers, athrottie for the air inlet actuated by the vane, and a force applied tothe vane for yieldingly retaining the vane in position to effect a wideopen air inlet when the pressure differential is less than thepredetermined requirement and to permit a partial closing of said airinlet when the predetermined pressure differential is exceeded.

7. An air inlet governor including, a cylindrical housing having an airinlet opening at one end and a due connecting opening in the other end,an intermediate air outlet opening in the cylindrical wall thereof andadapted to be connected with the air supply chamber of a heatingappliance, a shaft journalled coaxially of the housing, a vane fixed tothe shaft and having the respective sides responsive to pressure actingthrough the air outlet and through the flue connecting opening. apartition cooperating with the vane, a weight attached to the shaft foreffecting rota tion of the shaft in one direction, and a shutter on saidshaft controlling the effective area of the air inlet opening.

8. An air governor including. a housing having an air inlet opening. anopening adapted to be connected with a variable pressure zone and an airoutlet opening adapted to be connected with the air supply chamber of afuel burning appl ance, a shaft journalled in the housing, a vane fixedto the shaft and having the respec tive sides subjected to pressure ofsaid air supply chamber acting through the air outlet and through theopening connected with the variable pressure zone, and means actuated bysaid shaft controlling effective area of the air inlet opening.

9. An air governor including, a housing having an air inlet opening, anopening adapted to be connected with a variable pressure zone and an airoutlet opening adapted to be connected with an air supply chamber of afuel burning appliance, a shaft journalled in the housing, a vane fixedto the shaft and having the respective sides subjected to pressures ofsaid air supply chamber acting through the air outlet and through theopening connected with the variable pressure zone, means actuated bysaid shaft to throttle the air inlet opening, a pulley on the shaft, aflexible member connected with the pulley, and a weight attached to theflexible member for effecting rotation of the shaft in one direction.

10. In an apparatus of the character described, an air chamber subjectto variable pressure, a supply chamber for admitting combustionsupporting air, a fuel burning means in said chamber, the supply chamberhaving a restricted connection through the fuel burning means with thechamber subject to variable pressure and having an inlet, meanscontrolling said inlet, and means having connection with pressures inthe respective chambers and operably connected with the control meansfor controlling said inlet responsive to pressure differential in therespective chambers.

11. In a fuel burning appliance the combination of a combustion chamberhaving a flue connection adapted to be connected with a flue foreffecting variable pressures in said chamber, a burner having connectionwith said chamber, a supply chamber for admitting combustion supportingair to the burner and having an air inlet and providing an unrestrictedair flow from said inlet to the burner whereby the pressure at theburner is substantially that of the supply chamber, a movable vanehaving a side subject to pressure in the air supply chamber and having aside subject to pressure in the combustion chamber whereby the vanemoves responsive to pressure differential in the respective chambers, athrottle for the air inlet actuated by the vane, and means for applyinga force to the vane to balance the force of a desired operatingdifferential. a

12. In a fuel burning appliance, the combination of a combustion chamberhaving a variable internal pressure during operation, a supply chamberfor admitting combustion supporting air and having an inlet for exteriorair, means including a burner separating said chambers and providing arestricted air flow connection between said chambers, and meansresponsive to pressure differential between said chambers for governingthe flow of air through said inlet.

13. A governor of the character described including a housing having anair inlet in an end thereof and an air outlet in a side thereof adaptedto be connected with the air supply chamber of a fuel burning appliance,said housing having an opening adapted to be connected with a combustionchamber, means separating said air inlet and outlet from said openingincluding a fixed partition, 9. vane pivoted at one edge of thepartition and adapted to swing between the outlet and said openingresponsive to pressure differential effected through said air outlet andsaid opening, and a shutter having rigid connection with the vane andmovable over the inlet opening.

14. An air governor including a housing having an air inlet, and an airoutlet opening adapted to be connected with the air supply chamber of afuel burning appliance, said housing also having a fiue connectingopening, a shaft journalled in the housing, a vane aiiixed to the shaftand having the sides thereof subjected to pressure acting through theair outlet and through the flue connecting opening respectively, meansactuated by said shaft for controlling the effec tive area of the airinlet opening, balance means for said vane, and separate balance meansfor providing the force of the required differential.

15. An air outlet governor including a cylindrical housing having an airinlet opening at one Search Room end and a flue connection opening atthe other, said housing having an intermediate air outlet opening in thecylindrical wall thereof and adapted to be connected with the air supplychamber of a fuel burning appliance, a shaft Journalled coaxially of thehousing, a vane fixed to the shaft and having sides responsive topressures acting through the air outlet and through the flue connectingopening respectively, a shutter on said shaft controlling the effectivearea of the air inlet opening, a weight for balancing the vane andshutter, a member on the shaft having an arcuate portion, a flexibleconnection operating over the arcuate portion, and a weight on theflexible connection for balancing a predetermined resultant force ofsaid pressures.

RUSSELL MARTIN.

